I decided to go ahead and build a coop for next spring. The plan is to house 4 hens.
Overall dimensions will be 4' x 4' x 4' tall.

Bought some 2x3's.

I started by framing the floor .

Cut studs to length for the walls.

The daughter inspecting progress.

Ok , maybe she is playing chicken,

Framed the roof.
I added some 2x4's (the grey pieces) between the rafters. I will secure mesh wire around the roof section for ventilation and theses blocks will allow me somewhere to fasten the mesh while not leaving any large openings for predators.

In the following pics you can see the nesting boxes are attached, the framing for the chicken door in place. I also started on a litter box for the bottom that can be slid out from the rear and cleaned.
The roof is hinged so I can open it up and clean since it is not big enough for me to get into.

I'm wondering about roost now. I know they need to be higher than the nesting boxes but not sure how much head room the chickens will need. And do I need some sort of ladder for the chicks to get to the roost and nests?

If you're planning on 4 chickens, it looks like you've got room for a roost across the top highest point of the peak inside the coop. Most of my birds roosts are only a foot from the ceiling, and the ones that are lower are only lower by 4 inches or so. The highest ones are the most occupied.